I am hoping that you all can help. I reciently found this site and have spent some time reviewing post. They have been very helpful, but I am still having challenges.
First a bit about my pool…
4 year old 14,000 gallon pool with spa in Central FL. Finish is a blue quartz diamond brite. The pool is heated with solar and a Hayward Propane heater. Salt system for sanitation. Pool is usally 92F for 8 months a year. Pool turns 3 times a day during the summer and 2 during the winter. Tested weekly and very rare if outside of any of the values.
This is the 5th pool that I build as a General Contractor. I watched every step but the plaster finish. They showed up a day early and did it while I was at my real job. I have had some issues with the finish quality. Not bad, just not up to the par of the rest of the pool.
About the stain….
About 24 months ago I started to notice the deep end showing some darker areas (light tan). It looked like someone put a sand colored diamond brite into the hopper and accidently mixed it in. I blew it off as a bad install.
Over the course of the next 12 months it started to work its way on all of the bottom surfaces of the pool. It is a light tan / gray color. I dove the pool and tried pumice to scrub it off (no avail). I went to my local pool store to get a test kit (Jack’s). It took 3 weeks to get the right numbers on all of the conditions. Ran the test and nothing really hit. I called Jack’s and the tech asked a bunch of questions and recommended that I keep pH at 7.0-7.2, Alk at 80 or less and put 1 Qt of Magenta stuff in and every week following add 8 oz more for a total of 5 weeks. The stains did not lighten at all, but I did notice a very little bit blue green metal in the filter (guessing copper) as well as a bunch of sludge.
The tech recommended that I wait until until Spring to do another test because the water temp was getting too low for effective treatment.
So today, I tested using another kit. This was from Pinch a Penny (but by Jack’s) During the Iron/Cobalt test, I noticed a few light pink stains appear on the surface of the test stain (about 6 the size of rice grains). They are slowly fading, but no real change to the base stain.
The Stop Stain Test did nothing.
The O2 safe shock test (Oxidized Copper) ½ pouch of O2 safe shock for 2-3 minutes, followed by ½ packet of stop stains for a few seconds. I did notice a very light yellow ring around the pile of the O2 safe, I lightly brushed it with my hand to the next step in the spa so I could add the stop stains. The stop stains did not do anything. The stain looks about the same. Then when I stood up, I noticed that the 2nd step had dark yellow stains all over it. The dark yellow stains faded over 10 minutes with some minor brushing. Overall, I am having a hard time telling if the base stain is any lighter.
After reading the site, I did the Vitamin C test, and no change to the stain.
Here are the numbers for the pool as of Saturday. (Remember I was doing the Jack’s test so I had to get a few numbers pretty low)
Saturation Idx> .3
Total CL > .9
Free CL> .8
Total Alk> 97
Adj Total Alk> 74
Tot Hardness> 244
Usually pool sits at
Total and Free CL > 2
pH > 7.5
Total Alk > 100
Adj Alk >95
I am open to suggestions at this point. I am a bit leary about calling the tech back from Jack’s, because I felt like he was guessing. I offered to send pictures, but he said that with all of his experience he did not have to see the pool.